Characteristics Of Cognitive Dysfunctions Of Major Depressive Disorder Patients In General Hospital

Background:Major depressive disorders (MDD) is a common condition with a high rate of prevalence and disability, leading to heavy public health burden. Cognitive dysfunction is one of the most common symptoms of MDD as well as a major cause of disability. Researches have found processing speed, executive function and working memory to be the most reported areas of cognitive dysfunction, which may be affected by different features of MDD. Also, antidepressants have positive effects on cognitive dysfunction.Aim:This study aims to 1)find out cognitive areas affected in MDD patients in general hospital,2)discuss the effect of different features of MDD upon cognitive function, and 3)investigate the changes in cognitive function before and after antidepressants treatment.Methods:This study was conducted in general hospital. Patients met the DSM-Ⅳ criteria for MDD were continuously enrolled from psychological medicine clinic, and went through MCCB tests before and after eight weeks of antidepressants treatment. Healthy controls were recruited from the clinic and went through MCCB tests as well.Results:79 MDD patients and 31 healthy controls were enrolled in this study.48 MDD patients completed the eight-week antidepressants treatment and were reassessed with MCCB tests. A total of 27 male and 52 female MDD patients were enrolled, with an average age of (36.37±9.15) years old and depressive episode duration median of 8 months.63 had first-episode depression and 16 were recurrent patients. Average score of HAMD-17 was (22.92±4.81), and median of CGI was 4.0. Comparing to healthy controls, MDD patients scored significantly poorer in Color Trail Testsl (CTT1), Stroop Color Word Test (SCWT) and Hopkins Verbal Learning Test-Revised (HVLT-R). The score of Hamilton Rating Scale for Depression-17 Items (HAMD-17) correlates with the test results of Animal Fluency Test (AFT), Symbol Coding Test (SC), SCWT, HVLT-R and Brief Visuospatial Memory Test-Revised (BVMT-R). Number of recurrence correlates with the test results of CTTl and SCWT. MDD patients with anxious distress scored significantly lower than healthy controls in SCWT, HVLT-R and BVMT-R. Melancholic features, family history of psychiatric disorders, suicide risks, duration of current depression episode does not correlate with any test results. After 8 weeks of SSRIs treatment, MDD patients did significantly better in AFT, CTT1 and Continuous Performance Test-Identical Pairs (CPT-IP) than baseline and had no significant difference with healthy controls. However the test results were still significantly lower than healthy controls with HVLT-R and BVMT-R.Conclusions:Cognitive dysfunction exists in processing speed and verbal learning/memory area in MDD patients. Severity of depression correlates with processing speed, verbal learning/memory and visual learning/memory. Number of recurrence correlates with processing speed. MDD patients with anxious distress have more impaired cognitive function. There wasn’t specific correlation between melancholic features, family history of psychiatric disorders, suicide risks, duration of current depression episode and any area of cognitive function. SSRIs have a positive effect on processing speed and attention/vigilance, but no improvements in verbal learning/memory and visual learning/memory areas were observed.